/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.transformation.dag.transformer.multi;

import org.apache.iotdb.db.exception.query.QueryProcessException;
import org.apache.iotdb.db.mpp.transformation.api.LayerRowReader;
import org.apache.iotdb.db.mpp.transformation.api.YieldableState;
import org.apache.iotdb.db.mpp.transformation.dag.udf.UDTFExecutor;
import org.apache.iotdb.tsfile.exception.write.UnSupportedDataTypeException;
import org.apache.iotdb.tsfile.utils.Binary;
import org.apache.iotdb.udf.api.access.Row;

import java.io.IOException;
import java.util.Objects;

public class MappableUDFQueryRowTransformer extends UDFQueryTransformer {

    protected final LayerRowReader layerRowReader;
    private final boolean isLayerRowReaderConstant;

    public MappableUDFQueryRowTransformer(LayerRowReader layerRowReader, UDTFExecutor executor) {
        super(executor);
        this.layerRowReader = layerRowReader;
        this.isLayerRowReaderConstant = false;
    }

    @Override
    protected boolean cacheValue() throws QueryProcessException, IOException {
        if (!layerRowReader.next()) {
            return false;
        }

        if (!isLayerRowReaderConstant) {
            cachedTime = layerRowReader.currentTime();
        }

        if (layerRowReader.isCurrentNull()) {
            currentNull = true;
        } else {
            Row row = layerRowReader.currentRow();
            execute(row);
        }

        layerRowReader.readyForNext();
        return true;
    }

    @Override
    protected YieldableState yieldValue() throws QueryProcessException, IOException {
        final YieldableState yieldableState = layerRowReader.yield();
        if (!YieldableState.YIELDABLE.equals(yieldableState)) {
            return yieldableState;
        }

        if (!isLayerRowReaderConstant) {
            cachedTime = layerRowReader.currentTime();
        }

        if (layerRowReader.isCurrentNull()) {
            currentNull = true;
        } else {
            Row row = layerRowReader.currentRow();
            execute(row);
        }

        layerRowReader.readyForNext();
        return YieldableState.YIELDABLE;
    }

    private void execute(Row row) {
        executor.execute(row);
        Object currentValue = executor.getCurrentValue();
        if (Objects.isNull(currentValue)) {
            currentNull = true;
            return;
        }
        switch (tsDataType) {
            case INT32:
                cachedInt = (int) currentValue;
                break;
            case INT64:
                cachedLong = (long) currentValue;
                break;
            case FLOAT:
                cachedFloat = (float) currentValue;
                break;
            case DOUBLE:
                cachedDouble = (double) currentValue;
                break;
            case BOOLEAN:
                cachedBoolean = (boolean) currentValue;
                break;
            case TEXT:
                cachedBinary = (Binary) currentValue;
                break;
            default:
                throw new UnSupportedDataTypeException(tsDataType.toString());
        }
    }

    @Override
    public boolean isConstantPointReader() {
        return isLayerRowReaderConstant;
    }
}
